What does Dalton's Law state about a gas mixture?

Dalton's Law states that in a mixture of gases, the total pressure is equal to the sum of the partial pressures of each individual gas present. This principle is fundamental in understanding how different gases behave when mixed together and allows for calculation of the pressure exerted by each gas based on its proportion in the mixture. Each gas in the mixture exerts pressure independently of the others, and adding these individual pressures together gives the total pressure of the gas mixture. This concept is important in various applications, including respiratory physiology and aviation medicine, as it helps in predicting the behavior of gases under different conditions.

The other options do not accurately represent the essence of Dalton's Law. For instance, stating that the total pressure is simply equal to atmospheric pressure does not take into account the unique contributions of each gas in a mixture. Claiming that the gas with the highest pressure defines the total pressure ignores the additive nature of all contributing gases. Lastly, suggesting that the partial pressure of one gas can be ignored contradicts the core principle of Dalton's Law that every gas has an impact on the total pressure based on its own partial pressure.